The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

I will debate Rudd during election: Abbott

Opposition leader Tony Abbott says the only debate he will enter into with Kevin Rudd is across the floor of parliament or in election mode.

The reappointed prime minister on Thursday again challenged Mr Abbott to a national televised debate, saying he had booked the National Press Club for next Thursday in anticipation.

But while in WA for a Liberal party fundraiser and public appearance with Premier Colin Barnett, Mr Abbott refused to be drawn by Mr Rudd's taunts.

"I'm only too happy to debate Mr Rudd. If he wants to recall the parliament I will debate with him every day. If he wants to call the election, we can have an election debate," Mr Abbott said.

"I think it is great that Kevin will go to the Press Club and make a speech and answer some questions because so far he has basically been in hiding from serious scrutiny since he dragged down the prime minister."

As Mr Rudd left for Indonesia for high-level talks, Mr Abbott said that overseas was where the prime minister felt most comfortable.

"My guess is he will try and drag this out as long as possible, and he won't be able to resist the lure of international conferences," Mr Abbott told Fairfax radio.